Bordeaux mixture and method of preparing same.



UNITED STATES PATENT OFFICE.

FREDERIO J. SMITH, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO WILLIAM H.BOWKER, OF BOSTON, MASSACHUSETTS.

BORDEAUX MIXTURE AND METHOD OF PREPARING SAME.

SEECIEICATION forming part of Letters Patent No. 718,538, dated January13, 1903.

Application filed June 5,1901. Serial No- 63,308. (No specimens.)

. To all whom it may concern.-

Be it known that I, FREDEBIO J. SMITH, a citizen of the United States,residing at Elizabeth, in the county of Union and State of New Jersey,have invented certain new and useful Improvements in Bordeaux Mixtureand Method of Preparing the Same, of which the following is aspecification.

My invention relates to that class of chemical mixtures known asinsecticides or germicides, and particularly to the Bordeaux mixture, socalled; and its object is to produce an improvement therein, as will behereinafter more fully set forth.

The usual method of preparing the Bordeaux mixture now practiced is tomake a solution of blue vitriol, also a separate solution of causticlime and water, commonly known as milk of lime, and then to put the twomixtures together and apply.

I have discovered that unslaked calcium carbid may be ground and mixeddry with blue vitriol, also dry, and that the mixture thus made may bestored or transported in air-tight vessels or packages and kept until itis wanted for use, when water is added to it in the usual manner.

I have further discovered that when the calcium carbid in the mixture isslaked by the addition of water, as described, the lime reacts upon thecopper sulfate, producing the desired copper hydroxid, also that theheat produced by slaking in a large measure passes off with the escapeof the acetylene gas. By reason of this the copper hydroxid is preservedand possesses its active character as an insecticide,whereas if ordinarylime were slaked in the presence of blue vitriol the hydroxid would bedecomposed and its value as an insecticide lost.

I will now describe my improved methodof preparing my improved compound.

The blue vitriol is first heated to 212 Fahrenheit in an open vessel,with occasional stirring, until the water of crystallization has beendriven off so far as is possible at that temperature, when it will befound that the blue vitriol has lost about twenty-eight per cent. of itsoriginal weight. Further, it will be found that the original crystalshave crumbled, yielding a bluish-white and very hygroscopic powder. Thecalcium carbid is now mixed in the form of a powder with the powderedblue vitriol prepared as above described. This latter being veryhygroscopic .will take up any atmospheric moisture that may exist in thepackage in which the mixture is packed, and thereby prevent the calciumoarbid from becoming air-slaked by any moisture that may haveaccidentally found access.

In practice I have found the following proportions of ingredients make asatisfactory mixture: A quantity of crystallized copper sulfate weighingone hundred pounds is heated, as herein described, until it loses abouttwenty-eight per cent. of its original weight, due to the loss of waterof crystallization, leaving seventy-two pounds of dehydrated bluevitriol. Twenty-eight pounds of powdered calcium carbid is then mixedwith the seventy-two pounds of blue vitriol, care being taken to avoidundue exposure to air while mixing.

When the Bordeaux insecticide is wanted for use, one part by weight ofthe described mixture of powdered calcium carbid and blue vitriol ismixed with from fifteen to twenty parts of water in a suitable vessel.The escaping gas greatly assists in the mixing, and a Bordeaux mixtureis produced which is very suitable for spraying purposes. The Bordeauxmixture thus prepared will be brownish in color instead of the familiarblue; but after application the blue color will reappear, the changebeing due, according to my observation, to the mechanical separation ofparticles of carbon, which come from slaking the calcium carbid.

I claim- 1. The improvement in the art of preparing Bordeaux mixturewhich consists in subjecting blue vitriol to heat as described, wherebythe water of crystallization is driven off and the crystals crumbled toa powder, and mixing therewith powdered calcium carbid.

2. The improved product herein described consisting of a mixture ofpowdered blue vitriol and powdered calcium carbid.

In testimony whereof I have hereunto subscribed my name this l lth dayof May, 1901.

FREDERIO J. SMITH.

Witnesses:

HENRY J. MILLER, HANNAH N. F. MILLER.

